Best is rarely cheapest and the converse is generally applicable... especially with SSDs.
Use caution when conducting a web search, because 99% of "review" or "best product" sites are thinly veiled (or not so thinly veiled) interest-based targeted advertisements funded by the products they sell.
When researching them, be sure there is a way to update their firmware outside of Apple's occasionally required firmware updates. Again bear in mind Apple only develops firmware for the devices they incorporate in the products they sell, and that Apple does not support Macs incorporating anyone else's SSD. If you purchase a SSD from a manufacturer that only provides a Windows-based firmware update program, and you don't have a Windows PC, it may be difficult for you to update it.
For what it's worth the only SSDs I have used and can recommend are OWC / MacSales line of "Mercury Extreme Pro 6G" models to be specific. The oldest of them are now well beyond their five year warranty yet I have yet to have any of them fail, become slow, or fail to upgrade. Reports of failures are nearly unheard of.
You usually get what you pay for. All SSDs work well when they're new, otherwise they wouldn't get any good reviews at all. Their typical failure mode will be the sudden onset of poor performance, or failure to boot. Samsung's are definitely the cheapest. Reports of failures are common on this site and others.
Besides OWC's, Crucial is another respected manufacturer. Reports of failures are also nearly unheard of. I just don't happen to have any of them. There are other, less popular models that also seem to work well—judging by the apparent lack of problem reports.